MADRID, Sept. 9 -- The Spanish judge best known for indicting the former Chilean dictator Augusto Pinochet and al-Qaeda leader Osama bin Laden appeared in court Wednesday with the tables turned: This time he was a suspect, accused of overstepping his authority in a huge domestic case involving Spanish civil war atrocities.

A handful of supporters cheered Baltasar Garzón as he arrived at the Supreme Court for a closed-door session in what is a very rare instance of a formal legal investigation of a Spanish judge.

The court will now decide whether to continue with the probe.

In May, the Supreme Court agreed to investigate a complaint by an ultraconservative group that accuses Garzón of knowingly acting without jurisdiction in ordering a probe of executions and other abuses of civilians by forces loyal to Gen. Francisco Franco during the 1936-1939 civil war and in the early years of the Franco government.

Garzón's initiative last year -- Spain's first official investigation of such crimes -- was widely seen as seeking an indictment of the Franco regime itself. But the judge eventually bowed out in a dispute over jurisdiction.

Garzón, an investigating magistrate at the National Court, denies any wrongdoing. It is not known when the Supreme Court might decide whether to charge him.

Garzón is the most prominent symbol of Spain's doctrine of universal jurisdiction, which holds that heinous crimes such as torture or terrorism can be tried in this country even if they are alleged to have been committed elsewhere and had no link to Spain.

He used it in 1998 to go after Pinochet, having the former dictator arrested during a visit to London, although Britain ultimately refused to extradite him to Madrid for trial. Garzón indicted bin Laden in 2003 over the Sept. 11, 2001, terrorist attacks in the United States.

More recently, other judges at Garzón's court have used the principle to pursue current or former officials in Israel over an air force bombing in the Gaza Strip in 2002 that targeted and killed a Hamas leader but also killed 14 civilians; in the United States over treatment of prisoners at Guantanamo Bay, Cuba; and in China over alleged abuses in Tibet.

Amid growing complaints abroad that Spain was acting like a global cop, particularly from Israel and China, parliament scaled back the doctrine in June. Now, Spanish judges will be able to pursue universal justice cases only if the crimes involve Spanish victims or the alleged perpetrators are in Spain.

In August last year, Garzón turned his sights on a dark chapter of Spain's own past, launching an investigation into the disappearance or execution of tens of thousands of civilians during the war at the hands of Franco's supporters.